Project Summary Worldwide, youth living with HIV (YLWH) are poorly engaged in care and have worse health outcomes than adults do. Despite this, there is a lack of effective interventions to improve YLWH's engagement in care: keeping clinic appointment and adhering to antiretroviral therapy. Interventions to address this have largely focused on external motivations, incentives, and environment redesign. However, there is compelling evidence from social psychology that internal, rather than external, motivators are strongly associated with maintenance of positive and healthy behaviors. Motivational Interviewing (MI) has been used around the world to enhance the client's internal motivation to improve care engagement for numerous diseases, including HIV. In parallel, Community Health Workers (CHWs) have demonstrated the capacity to reach vulnerable, rural populations, who are less likely to engage in care. However, a common finding is that MI training without ongoing supervision leads to skill decay, and CHWs return to judgmental advice-giving, which can alienate YLWH. Building on our work over the last ten years in rural Nepal and India, we propose to address these challenges by developing a Community-based mHealth Motivational Interviewing Tool for HIV- positive youth (COMMIT+). COMMIT+ will be used by CHWs to: 1) obtain decision-support to deliver MI for individual cases in the community, and 2) capture consented audio recordings of client interactions for review and feedback by their supervisors so CHWs can maintain MI skills beyond the initial training period. In the proposed study, we will develop, study, and refine COMMIT+ for a future multi-site trial to improve care engagement about YLWH. We will pursue two aims: 1) To develop the Community- based mHealth Motivational Interviewing Tool for HIV-positive youth (COMMIT+) to support community health workers in using and sustaining motivational interviewing skills; and 2) To assess the acceptability and feasibility of COMMIT+ among YLWH, CHWs, and their supervisors to improve adherence to antiretroviral therapy, clinic appointments, and CD4 counts. Using human-centered design thinking, we will iteratively develop COMMIT+ and test it at a site with one of the highest incidence and prevalence of HIV in Nepal, and where CHWs already use mobile devices to assist in clinical tasks. At completion, we expect to have adapted COMMIT+ and demonstrated its acceptability and feasibility among YLWH, CHWs, and their supervisors, and to have prepared an application for a multi-site trial in Nepal and India, where the MPIs have worked for over a decade.